// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_ANIMATION_INK_DROP_ANIMATION_OBSERVER_H_
#define UI_VIEWS_ANIMATION_INK_DROP_ANIMATION_OBSERVER_H_

#include <string>

#include "base/macros.h"
#include "ui/views/animation/ink_drop_state.h"
#include "ui/views/views_export.h"

namespace views {

// Pure-virtual base class of an observer that can be attached to
// InkDropAnimations.
class VIEWS_EXPORT InkDropAnimationObserver {
public:
    // Enumeration of the different reasons why an InkDropAnimation has finished.
    enum InkDropAnimationEndedReason {
        // The animation was completed successfully.
        SUCCESS,
        // The animation was stopped prematurely before reaching its final state.
        PRE_EMPTED
    };

    // Notifies the observer that an animation for |ink_drop_state| has started.
    virtual void InkDropAnimationStarted(InkDropState ink_drop_state) = 0;

    // Notifies the observer that an animation for |ink_drop_state| has finished
    // and the reason for completion is given by |reason|. If |reason| is SUCCESS
    // then the animation has progressed to its final frame however if |reason|
    // is |PRE_EMPTED| then the animation was stopped before its final frame. In
    // the event that an animation is in progress for ink drop state 's1' and an
    // animation to a new state 's2' is triggered, then
    // InkDropAnimationEnded(s1, PRE_EMPTED) will be called before
    // InkDropAnimationStarted(s2).
    virtual void InkDropAnimationEnded(InkDropState ink_drop_state,
        InkDropAnimationEndedReason reason)
        = 0;

protected:
    InkDropAnimationObserver() { }
    virtual ~InkDropAnimationObserver() { }

private:
    DISALLOW_COPY_AND_ASSIGN(InkDropAnimationObserver);
};

// Returns a human readable string for |reason|.  Useful for logging.
std::string ToString(
    InkDropAnimationObserver::InkDropAnimationEndedReason reason);

} // namespace views

#endif // UI_VIEWS_ANIMATION_INK_DROP_ANIMATION_OBSERVER_H_
